Salaam
I am from India and a long time back I was invited to a function as a chief guest and as part of the inaugural function I was told to light a lamp. This is a tradition in many parts of India where they start any function with this ceremony. The reason for this I think is religious (https://www.quora.com/What-is-the-significance-of-lighting-a-lamp-before-a-function-or-a-ceremony)
Does doing this would have made me a kaafir. I repented for this but am not sure whether doing the taubah I had the intention that if such a situation is presented before me in future, I will never do this again. Does this mean that my repentance was not accepted and I continued to be an apostate.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Lighting the lamp or the torch you mentioned doesn't make you a disbeliever, even if some people associate it with disbelief doctrines, as long as you didn't believe in anything related to that doctrine, but rather did it as a way of following traditions.

We think your question is due to whispers which we have already advised you to ignore and not to give in to them. We made this clear to you in the answer to your previous question No. 2626653. We reiterate our advice to you to repel and ignore those whispers, especially in issues related to disbelief.

Allah Knows best.